Waveguide electrooptic modulator for CO2 lasers

This paper reports on an intracavity CdTe electrooptic modulator being developed for a 10.6-µm transmitter operating at 300 Mbps between low altitude and synchronous satellites. As the transmitter laser is a waveguide CO2 device,1 a waveguide mode of propagation in the modulator rod is used for optical confinement.2 This design, shown in Fig. 1, is a modification of the open resonator structure with an intracavity lens used in conventional transmitters. The waveguide configuration removes the limit on modulator length imposed by open resonator diffraction, eliminates the safety factor in the transverse dimension of the rod, and avoids loss arising from the intracavity lens.